Vibrating roller

ABSTRACT

A vibrating roller mechanism that includes a roller drum and a vibrating device mounted on the drum to form a tuned two-mass system in resonance. This arrangement provides for a high amplitude of vibration of the roller drum with the use of a vibrating device of relatively small mass.

United States Patent Fransson 1 Nov. 21, 1972 [54] VIBRATING ROLLER [56]References Cited [72] Inventor: .ohrziny Fransson, Akersberga, UNITEDSTATES PATENTS we en 3,543,656 12/1970 Roettger ..94/50 V 1 Asslgfleelgktigbolaget Vibm-Verken, $01M, 3,195,429 7/1965 Cowley ..94/50 v we en22 Fl (1; 0 L 12, 1970 Primary Examiner-Jacob L. Nackenoff- E i A e l N5824 Attorney-Brumbaugh, Graves, Donohue & Raymond v [57] ABSTRACT [30]Foreign Application Priority Data A vibrating roller mechanism thatincludes a roller Oct. 8, 1969 Sweden ..13s4s drumand a vibrating devicel f form a tuned two-mass system in resonance. ThlS arrangement providesfor a high amplitude of vibration of the roller drum with the use of aVibrating device of [58] Field of Search ..94/50, 50 v re'amiely Smallmass 17 Claims, 7 Drawing Figures PATENTEU 2 3 703 128 SHEET 1 BF 3VIBRATING ROLLER BACKGROUND OF THE INVENTION Rollers for compactingearth and the like are preferably of the vibrating type for improvedefficiency. Vibrations have been provided in such rollers by using oneor more rotating eccentric shafts driven by a separate engine. Therotating shafts are mounted and supported relative to the roller drum insuch a manner that the centrifugal forces generated by rotation of theshafts are transmitted directly to the drum through the shaft bearings.The use of small bearings for journaling the relatively high speedshafts has severely limited the magnitude of the centrifugal forces thatcan be coupled therethrough to the drum.

In still another prior vibrating roller, a circular ball race is fixedto the inside of the roller drum. By driving one or more balls along therace by a driver mounted on a central drive shaft in the roller drum,centrifugal forces are transmitted directly to the shell of the rollerdrum, thereby unloading the rapidly rotating bearings of the driveshaft. However, this type of vibratory mechanism requires carefulassembly and frequent maintenance and, moreover, is difficult todismantle, repair and reassemble.

SUMMARY OF THE INVENTION The present invention overcomes the problemsinherent in prior vibrating roller mechanisms through the use of avibrating roller mechanism comprised of a twomass system in resonance.In exemplary forms of the invention, the vibrations are generated by arotating eccentric shaft or by a crank mechanism.

More particularly, interacting and flexibly connected masses in thetwo-mass system consist of the roller drum on the one hand and avibrating device (mass) vibrating out of phase relative to the drum onthe other. The ratio between the two masses is so selected that thevibration system is unaffected by variations in the nature of the groundbeing compacted, the mass vibrating out of phase being relatively smallcompared to that of the drum.

In the case of the vibration system using an eccentric shaft in ahousing, preferably the shaft is driven at a speed close to the naturalfrequency of the system, i.e., the roller drum, springs and housing(vibrating device), or a speed that deviates so little from thisfrequency that a suitable vibration amplitude of the roller drum isobtained. With this arrangement, high vibrating forces and largevibration amplitudes of the drum can be generated with considerably lesspower than that required in prior vibratory mechanisms. Moreover, sincefar less power is transmitted directly through the small and rapidlyrotating eccentric shaft bearings, longer service life is obtained fromsuch bearings.

In accordance with certain embodiments of the inventive vibrating rollermechanism, the vibrating device is mounted above and resiliently coupledto the roller drum. Due to the low speed of rotation of the drum, largeand strong bearings, having an improved capacity for transmitting largecentrifugal forces, are used to journal the drum axle. The vibratingforces from the vibrating device are transmitted through the resilientcoupling to such large slowly rotating bearings of the roller drum tothe drum, which is in contact with the ground or some other surface.

In accordance with the invention, vibrations can also be generated by aweighted member vibrated by a crank mechanism which, as in the case ofthe rotating eccentric shaft, is driven at a speed close to the naturalfrequency of the vibration system or deviates so little from suchfrequency that the desired amplitude of drum vibration is obtained. Withthis arrangement, the weighted member of suitable mass, corresponding tothe eccentric shaft housing, is set in vibration by the crank mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of a towedroller incorporating a vibrating roller mechanism in accordance with theinvention;

FIG. 2 is an elevational view, partly in section, of the roller of FIG.1 as viewed from the right-hand side of FIG. 1;

FIG. 3 is a cross-sectional view of a vibrating housing and springassembly incorporated in the roller of FIG. 1 taken along view line 33of FIG. 2;

FIG. 4 is a longitudinal cross-section of a roller drum in accordancewith the invention having a vibrating device located within the drum;

FIG. 5 is a composite view of the roller drum of FIG. 4, showing in theright-hand position a vertical sectional view taken through the middleof the roller drum and looking outward toward the right-hand end of FIG.4 and in the left-hand portion an elevational view of the right-handside of the roller drum of FIG. 4 with the frame broken away forclarity;

FIG. 6 shows another embodiment of the invention which includes a rollerdrum mounting a vibrating device of modified design; and

FIG. 7 is a side view of the roller drum of FIG. 6 partly broken away toshow a partial cross-section along the view line 77 of FIG. 6.

DESCRIPTION OF THE INVENTION Referring to a typical embodiment of theinvention with particular reference to FIGS. 1, 2 and 3, a roller drum 1includes an axle la rotatably mounted or journaled in bearings 3 whichare connected to a frame 2. Vibrations are imparted to the roller drum,as explained hereinafter, by a vibrating device or unit 4 located abovethe drum. An engine 5 mounted on the frame 2 drives the vibrating unit 4through pulleys 7, 8 and 9 connected by drive belts 6a and 6b. Thepulley 7 is mounted on the engine 5, the pulley 8 on the frame 2 and thepulley 9 on an eccentric shaft 13 (FIG. 2).

A yoke 10, supported by the bearings 3, carries the vibrating unit 4above the roller drum 1. To maintain the vibrating device 4 in position,resilient couplings 12 formed of rubber, for example, flexibly mount theyoke 10 to the frame 2.

The vibrating unit 4 is formed by the eccentric shaft 13 rotatablymounted in an eccentric housing 11, and both the housing and shaftextend along the width of the drum. Bearings 14 positioned in each endof the housing 11 rotatably support the shaft 13. A pair of horizontalflanges 11a at each end of the housing 11 are resiliently mounted in apair of spring assemblies 15 (FIG. 3). Frames 16, secured to the yoke 10at each end of the housing 11, support the spring assemblies 15.

In order to obtain a highly progressive spring rate and therebyeliminate the effect of the drum supporting surface on the amplitude ofdrum vibration, stops 17 are incorporated in the frames 16 and areengaged by the housing 11 after its vibrations have reached a certainamplitude.

In operation of the vibrating roller mechanism shown in FIGS. 1, 2 and3, the driving engine 5 rotates the eccentric shaft 13 through thepulleys 7, 8 and 9, and the belts 6a and 6b, thereby causing theeccentric: housing 11 to vibrate. The spring assemblies 15 transmit suchvibrations to the bearing frame 16, the yoke 10 and the roller drum 1.Note that the two-mass system consists on the one hand of the eccentrichousing 11 and the eccentric shaft 13 and on the other of the bearingframes 16, the yoke 10 and the roller drum 1, the two masses beingresiliently connected by the spring assemblies 15. The two masses willvibrate out of phase with the mutual vibration amplitudes of the massesbeing partly determined by the relationship between the magnitudes ofthe masses. As is well known, tuning the frequency of the periodicforces generating the vibrations produces resonance effects, when suchperiodic forces are close to the natural frequency of the vibrationsystem, with the result that relatively small periodic forces suffice toprovide very high vibration amplitudes.

In other words, by selecting (1) a suitable relationship between themagnitudes of the two masses, i.e., the eccentric housing 11 andcontents on the one hand and the roller drum 1 and attached structureson the other, (2) a suitable choice of spring rate of the springassemblies between the two masses, and (3) a suitable frequency ofvibration, a desired amplitude of vibration of the roller drum isproduced. These factors are determined and designed into the roller atthe time of its manufacture, and generally are not subsequently changed.Moreover, the small bearings 14 are not unduly loaded by vibratingforces, the high vibratory forces being transmitted through the largeheavy duty bearings 3.

Although the eccentric shaft 13 generates circular vibrations, theresilient spring assemblies 15 provide for transmission of the verticalcomponents of such vibratory forces to the roller drum. With thisarrangement, the so-called bulge which in the past has been formed aheadof a vibrating compacting roller drum, is eliminated.

In another embodiment of the invention shown in FIGS. 4 and 5, in whichparts similar to those of FIGS. 1 through 3 have been designated byprimed reference numerals, an eccentric housing 11', located centrallywithin a roller drum 1, is flexibly mounted at its ends by resilientrings 18. A sleeve-shaped section 19 with central opening 20, formed ineach end plate 21 of the drum 1, on one side provides a support for theresilient rings 18 and on the other side forms a stub axle 22 journaledby bearing 3. Resilient couplings 12' mount the bearings to frame 2'.

An eccentric shaft 13 is rotatably mounted by bearings 14' inside of theeccentric housing 11. One end of the shaft 13' protrudes through theopening 20 to receive a pulley 21 which is adapted to be driven by abelt to impart rotary motion to the shaft.

In the embodiment of FIGS. 4 and 5, the two masses constituting thetwo-mass system consists of the eccentric housing 11' and eccentricshaft 13' (together forming the vibrating device) on the one hand andthe roller drum 1' and bearings 3 on the other, the two masses beingresiliently coupled by the springs (resilient rings) 18. Operation ofthis embodiment is substantially the same as that described inconnection with the embodiment of the invention shown in FIGS. 1, 2 and3, except that the vibrations are transmitted directly to the drum 1'and such vibrations are not limited to vertical vibrations.

In still a further embodiment of the invention shown in FIGS. 6 and 7vibrations are provided by a weighted member actuated by a crankmechanism. Note that elements corresponding to those shown in FIGS. 1through 3 have been designated by double primed reference numerals.Examining the structure shown in FIGS. 6 and 7 in greater detail, ashaft 22 carries at each end a crank 23 journaled by a bearing 24a to aconnecting rod 24. A frame 26 carried by a yoke 10" mounts a pair ofbearings 25 on each side of the crank 23 to rotatably support the shaft22. A pulley 27 on one end of the shaft 22 is adapted to be driven bythe driving engine 5 (FIG. 1) through a suitable belt transmission.

A solid member 29 (the vibrating device), extending the width of theroller drum 1", is formed at each end with flattened portions 29a havingopenings 29b therein. The connecting rod 24 extends through the opening29b, as shown in FIG. 7, and includes a plate 240 at its upper endsecured by a nut 24b. Resilient couplings 28, for example rubber blocks,resiliently connect the rod 24 to the flattened portions 29a of thesolid member 29.

Also forming part of the solid member 29 are flanges 290 depending fromflattened portions 29a and extending horizontally at each end intospring assemblies 30 mounted in the frame 26.

In this embodiment of the invention, the two-mass system is constitutedon the one hand by the weighted member 29 and on the other by the crankmechanism, the frame 26, the yoke 10" and the drum 1", the two massesbeing resiliently coupled by the spring assemblies 30. Vibrationsgenerated by the member 29 are transmitted by the spring assemblies 30to the frame 26, the yoke 10" and the drum 1''.

As discussed in connection with the operation of the FIGS. 1 through 3embodiment of the invention, the frequency, spring rate and magnitude ofthe two masses constituting the vibrating system are selected so that adesired vibration amplitude of the roller drum is obtained. Note that inthis embodiment, as in the embodiment of FIGS. 1 through 3, onlyvertical vibrations are transmitted to the roller drum. Also note thatlarge vibrating forces are transmitted through the heavy duty bearings3" and not through the small bearings 25.

It will be apparent that the inventive vibrating roller mechanism cantake other forms not shown and described herein. Therefore, theinvention is not to be limited to the specific apparatus disclosed butis to be defined by the appended claims.

I Claim:

1. Vibrating roller mechanism comprising roller drum means, including aroller drum, constituting a first mass; a vibrating device constitutinga second mass; spring means resiliently coupling the vibrating device tothe roller drum means in vibration transmitting relation; the rollerdrum means, the vibrating device and the spring means forming a two-massvibra tion system having a predetermined natural resonant frequency; andmeans for vibrating the vibrating device at a frequency close enough tothe natural resonant frequency of the two-mass system to produce anamplification of the amplitude of vibration of the roller drum due toresonance effects in the two-mass system.

2. Vibrating roller mechanism as defined in claim 1, wherein thevibrating device comprises an eccentric shaft rotatably mounted in ahousing.

3. Vibrating roller mechanism as defined in claim 2, wherein the springmeans mounts the housing on and couples the housing to the roller drummeans.

4. Vibrating roller mechanism as defined in claim 3, wherein:

the housing is located above and in generally vertical alignment withthe rotational axis of the roller drum and includes generally horizontalsurfaces; the roller drum means includes vertically spaced, generallyhorizontal members positioned above and below the horizontal housingsurfaces; and

the spring means is interposed between the horizontal housing surfacesand the horizontal members of the roller drum means wherebysubstantially only vertical vibrations are transmitted to the rollerdrum means.

5. Vibrating roller mechanism as defined in claim 3, in which the rollerdrum means includes stop means positioned in spaced relation to thehousing for limiting the amplitude of vibration of the housing to apredetermined magnitude.

6. Vibrating roller mechanism as defined in claim 1, in which isprovided a frame; the roller drum means including axle means extendingfrom each end of the roller drum, bearings journaling the axle means andcoupled to the frame, and a yoke supported by the bearings; and thespring means coupling the vibrating device to the yoke.

7. Vibrating roller mechanism as defined in claim l, in which isprovided a frame; the roller drum means including axle means extendingfrom each end of the roller drum, bearings journaling the axle means andcoupled to the frame, and end plates of the roller drum includingsupporting means; and the spring means being mounted in the supportingmeans and coupling the vibrating device to the end plates.

8. Vibrating roller mechanism as defined in claim 1, in which thevibrating device comprises a weighted member having a selected mass; andthe vibrating means includes a rotatable shaft carrying a crank and aconnecting rod on the crank resiliently coupled to the weighted member;and the spring means coupling the weighted member to the roller drummeans.

9. Vibrating roller mechanism as defined in claim 8, wherein:

the weighted member is located above and in generally vertical alignmentwith the rotational axis of the roller drum and includes generallyhorizontal surfaces;

the roller drum means includes vertically spaced,

generally horizontal members positioned above and below the horizontalsurfaces of the weighted member; and

the spring means is interposed between the horizontal weighted membersurfaces and the horizontal members of the roller drum means wherebysubstantially only vertical vibrations are transmitted to the rollerdrum means.

10. Vibrating roller mechanism comprising a frame; a roller drum havingaxle means; bearings journaling the axle means and coupled to the frame;a yoke carried by the bearings; a vibrating device; spring meanscoupling the vibrating device to the yoke in vibration transmittingrelationship; a two-mass vibration system having a predetermined naturalresonant frequency being formed by the resiliently coupled roller drum,bearings and yoke on the one hand and the vibrating device on the other;and means for vibrating the vibrating device at a frequency close enoughto the natural resonant frequency of the two-mass system to produce anamplification of the amplitude of vibration of the roller drum due toresonance effects in the two-mass system.

11. Vibrating roller mechanism as defined in claim 10, wherein thevibrating device comprises an eccentric shaft rotatably mounted in ahousing.

12. Vibrating roller mechanism as defined in claim 11, wherein:

the housing is located above and in generally vertical alignment withthe axle of the roller drum and includes generally horizontal surfaces;

the yoke includes vertically spaced, generally horizontal memberspositioned above and below the horizontal housing surfaces; and

the spring means is interposed between the horizontal housing surfacesand the horizontal yoke members, whereby substantially only verticalvibrations are transmitted to the roller drum.

13. Vibrating roller mechanism as defined in claim 11, in which thevibrating device comprises a weighted member having a selected mass; andthe vibrating means includes a rotatable shaft carrying a crank and aconnecting rod on the crank resiliently coupled to the weighted member.

14. Vibrating roller mechanism as defined in claim 13, wherein:

the weighted member is located above and in generally vertical alignmentwith the rotational axis of the roller drum and includes generallyhorizontal surfaces;

the yoke includes vertically spaced, generally horizontal memberspositioned above and below the horizontal surfaces of the weightedmember; and

the spring means is interposed between the horizontal weighted membersurfaces and the horizontal yoke members, whereby substantially onlyvertical vibrations are transmitted to the roller drum.

l5. Vibrating roller mechanism comprising a frame; a roller drum havingaxle means; bearings journaling the axle means and coupled to the frame;end plates included in the roller drum, the end plates includingsupporting sleeves; a vibrating device within the drum; spring means inthe supporting sleeves mounting and coupling the vibrating device to theroller drum in vibration transmitting relationship; a two-mass vibral6.Vibrating roller mechanism as defined in claim 15, wherein the vibratingdevice comprises an eccentric shaft rotatably mounted in a housing.

17. Vibrating roller mechanism as defined in claim 16, wherein thespring means mounts the housing in the supporting sleeves.

1. Vibrating roller mechanism comprising roller drum means, including aroller drum, constituting a first mass; a vibrating device constitutinga second mass; spring means resiliently coupling the vibrating device tothe roller drum means in vibration transmitting relation; the rollerdrum means, the vibrating device and the spring means forming a two-massvibration system having a predetermined natural resonant frequency; andmeans for vibrating the vibrating device at a frequency close enough tothe natural resonant frequency of the two-mass system to produce anamplification of the amplitude of vibration of the roller drum due toresonance effects in the twomass system.
 1. Vibrating roller mechanismcomprising roller drum means, including a roller drum, constituting afirst mass; a vibrating device constituting a second mass; spring meansresiliently coupling the vibrating device to the roller drum means invibration transmitting relation; the roller drum means, the vibratingdevice and the spring means forming a two-mass vibration system having apredetermined natural resonant frequency; and means for vibrating thevibrating device at a frequency close enough to the natural resonantfrequency of the two-mass system to produce an amplification of theamplitude of vibration of the roller drum due to resonance effects inthe two-mass system.
 2. Vibrating roller mechanism as defined in claim1, wherein the vibrating device comprises an eccentric shaft rotatablymounted in a housing.
 3. Vibrating roller mechanism as defined in claim2, wherein the spring means mounts the housing on and couples thehousing to the roller drum means.
 4. Vibrating roller mechanism asdefined in claim 3, wherein: the housing is located above and ingenerally vertical alignment with the rotational axis of the roller drumand includes generally horizontal surfaces; the roller drum meansincludes vertically spaced, generally horizontal members positionedabove and below the horizontal housing surfaces; and the spring means isinterposed between the horizontal housing surfaces and the horizontalmembers of the roller drum means whereby substantially only verticalvibrations are transmitted to the roller drum means.
 5. Vibrating rollermechanism as defined in claim 3, in which the roller drum means includesstop means positioned in spaced relation to the housing for limiting theamplitude of vibration of the housing to a predetermined magnitude. 6.Vibrating roller mechanism as defined in claim 1, in which is provided aframe; the roller drum means including axle means extending from eachend of the roller drum, bearings journaling the axle means and coupledto the frame, and a yoke supported by the bearings; and the spring meanscoupling the vibrating device to the yoke.
 7. Vibrating roller mechanismas defined in claim 1, in which is provided a frame; the roller drummeans including axle means extending from each end of the roller drum,bearings journaling the Axle means and coupled to the frame, and endplates of the roller drum including supporting means; and the springmeans being mounted in the supporting means and coupling the vibratingdevice to the end plates.
 8. Vibrating roller mechanism as defined inclaim 1, in which the vibrating device comprises a weighted memberhaving a selected mass; and the vibrating means includes a rotatableshaft carrying a crank and a connecting rod on the crank resilientlycoupled to the weighted member; and the spring means coupling theweighted member to the roller drum means.
 9. Vibrating roller mechanismas defined in claim 8, wherein: the weighted member is located above andin generally vertical alignment with the rotational axis of the rollerdrum and includes generally horizontal surfaces; the roller drum meansincludes vertically spaced, generally horizontal members positionedabove and below the horizontal surfaces of the weighted member; and thespring means is interposed between the horizontal weighted membersurfaces and the horizontal members of the roller drum means wherebysubstantially only vertical vibrations are transmitted to the rollerdrum means.
 10. Vibrating roller mechanism comprising a frame; a rollerdrum having axle means; bearings journaling the axle means and coupledto the frame; a yoke carried by the bearings; a vibrating device; springmeans coupling the vibrating device to the yoke in vibrationtransmitting relationship; a two-mass vibration system having apredetermined natural resonant frequency being formed by the resilientlycoupled roller drum, bearings and yoke on the one hand and the vibratingdevice on the other; and means for vibrating the vibrating device at afrequency close enough to the natural resonant frequency of the two-masssystem to produce an amplification of the amplitude of vibration of theroller drum due to resonance effects in the two-mass system. 11.Vibrating roller mechanism as defined in claim 10, wherein the vibratingdevice comprises an eccentric shaft rotatably mounted in a housing. 12.Vibrating roller mechanism as defined in claim 11, wherein: the housingis located above and in generally vertical alignment with the axle ofthe roller drum and includes generally horizontal surfaces; the yokeincludes vertically spaced, generally horizontal members positionedabove and below the horizontal housing surfaces; and the spring means isinterposed between the horizontal housing surfaces and the horizontalyoke members, whereby substantially only vertical vibrations aretransmitted to the roller drum.
 13. Vibrating roller mechanism asdefined in claim 11, in which the vibrating device comprises a weightedmember having a selected mass; and the vibrating means includes arotatable shaft carrying a crank and a connecting rod on the crankresiliently coupled to the weighted member.
 14. Vibrating rollermechanism as defined in claim 13, wherein: the weighted member islocated above and in generally vertical alignment with the rotationalaxis of the roller drum and includes generally horizontal surfaces; theyoke includes vertically spaced, generally horizontal members positionedabove and below the horizontal surfaces of the weighted member; and thespring means is interposed between the horizontal weighted membersurfaces and the horizontal yoke members, whereby substantially onlyvertical vibrations are transmitted to the roller drum.
 15. Vibratingroller mechanism comprising a frame; a roller drum having axle means;bearings journaling the axle means and coupled to the frame; end platesincluded in the roller drum, the end plates including supportingsleeves; a vibrating device within the drum; spring means in thesupporting sleeves mounting and coupling the vibrating device to theroller drum in vibration transmitting relationship; a two-mass vibrationsystem having a predetermined natural resonant frequency being formed bythe resiliently coupled roller drum on the one haNd and the vibratingdevice on the other; and means for vibrating the vibrating device at afrequency close enough to the natural resonant frequency of the two-masssystem to produce an amplification of the amplitude of vibration of theroller drum due to resonance effects in the two-mass system. 16.Vibrating roller mechanism as defined in claim 15, wherein the vibratingdevice comprises an eccentric shaft rotatably mounted in a housing.